Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses plan requirements, monthly quota, and 60-second cooldown—critical operational constraints not covered by the openWorldHint annotation. It also clarifies ownership scoping. This adds meaningful behavioral context beyond what annotations provide; a minor gap is not describing output format, but with no output schema, that is somewhat expected.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is compact, with the main purpose first, followed by constraints. It avoids verbosity but could be slightly improved by front-loading the ownership scoping, which is currently at the end. Overall, efficient and clear.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter tool with no output schema and simple annotations, the description covers the essential operational aspects: purpose, constraints, and scoping. The lack of output format description is not critical, and the plan/quota/cooldown details add completeness. Slight room for improvement would be to mention what the report includes, but it is adequate.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already describes monitor_id as the UUID of the monitor, and coverage is 100%. The description does not add further detail beyond what the schema provides, so baseline 3 is appropriate. No extra semantics needed given only one parameter.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states it generates a plain-language CrUX trend report for a monitor, using a specific verb and resource. It is distinct from siblings like get-crux-data (which likely returns raw data) and summarize-health (which likely covers different metrics), though it doesn't explicitly name these alternatives.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description specifies it is scoped to the token owner's monitors, which is important usage context. It implies when to use (when a readable trend summary is needed) but does not explicitly state when not to use it or mention alternatives like get-crux-data for raw data.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.